Ductile Detailing Research Articles

Analysis of Strong Motion Records from Uttarkashi Earthquake for Assessment of Code Provisions for Different Seismic Zones

Strong motion records have been obtained at 13 stations during the Uttarkashi earthquake of October 20, 1991 (magnitude 6.6). A study has been conducted on these time histories to assess the codal provisions in India. Emphasis of the study is on evaluating relative consistency of design provisions for different seismic zones in India. The average response spectra from this earthquake show concentration of significantly more energy in low period range and less energy in high period range. The magnitude of seismic design force for zones I, II, and III is consistent while it is too low for zone IV; no records were obtained in area with shaking intensity corresponding to zone V. It is seen that for buildings in zones I, II, and III, the present design provisions may be lowered either by relaxing the requirement of special ductile detailing, or by reducing the design force. On the other hand, design provisions for zone IV need to be revised upwards.

Diaphragms in seismic resistant buildings

The paper deals with the design requirements for reinforced concrete diaphragms. Although diaphragms are primary members of the seismic force resisting system, ductile detailing of diaphragms is not considered to be required. While the design of diaphragms in regular framed buildings is straightforward, the analysis of transfer diaphragms involves more complex design criteria. Special considerations related to precast diaphragms are dealt with in more detail.

A procedure for the analysis and design of ductile reinforced concrete frame buildings of moderate height

A procedure is presented in step by step form for designing and detailing a reinforced concrete frame building to the requirements of DZ4203 (Draft New Zealand loading code). Consideration is given for adequate ductility by means of a capacity design approach to all members to obtain a large number of plastic hinges which are detailed to dissipate energy without brittle failure. Further ductile detailing is given for all other locations where accidental hinges could occur and to limit excessive deflections that may result from deterioration of beam column joints.